67491-64-9Relevant articles and documents
Rhodium-catalyzed addition-cyclization of hydrazines with alkynes: Pyrazole synthesis via unexpected C-N bond cleavage
Li, Deng Yuan,Mao, Xiao Feng,Chen, Hao Jie,Chen, Guo Rong,Liu, Pei Nian
supporting information, p. 3476 - 3479 (2014/07/21)
Rhodium-catalyzed addition-cyclization of hydrazines with alkynes has been achieved to afford highly substituted pyrazoles under mild conditions. The cascade reaction involves two transformations: addition of the C-N bond of hydrazines to alkynes via unex
Synthesis and characterization of some pyrazole derivatives of 1,5-diphenyl-1H-pyrazole-3,4-dicarboxylic acid
Kasimogullari, Rahmi,Arslan, B. Seckin
experimental part, p. 1040 - 1048 (2010/10/21)
(Chemical Equation Presented) Compound of 4-(ethoxycarbonyl)-1,5-diphenyl- 1H-pyrazole-3-carboxylic acid 2 was obtained from the reaction of ethyl 4,5-dioxo-2-phenyl-4,5-dihydrofuran-3-carboxylate and 1-benzylidene-2- phenylhydrazine. A number of substitute pyrazole dicarboxylic acid derivatives (4, 5a-c, 6, 7, 8, 9a-m, 10, 11, 12, 13, 14) were synthesized from 1,5-diphenyl-1H-pyrazole-3,4-dicarboxylic acid 3 which was prepared from basic hydrolysis of 2. Structures of synthesized compounds were characterized by 1H NMR, 13C NMR, Mass, FTIR, and elemental analysis.
Nucleophilic β-oniovinylation: Concept, mechanism, scope, and applications
Weiss, Robert,Bess, Matthias,Huber, Stefan M.,Heinemann, Frank W.
, p. 4610 - 4617 (2008/09/20)
Insertion of an electron-deficient alkyne A-C≡C-A (A = CO 2Me) into the C-L+ bond of an acyl-onio salt R-C(O)-L + (R = Ar, OAlk; L = 4-dimethylaminopyridine, PPh3) has for the first time been achieved in the presence of catalytic amounts of the nucleophile L. For R = OMe, a second insertion of the alkyne was observed. X-ray structures were obtained for a number of such β-oniovinylation products. Depending on reaction conditions, preferentially E- or Z-stereochemistry was observed, the Z-isomer being the thermodynamically more stable. A mechanism for this novel insertion reaction is presented which accounts for the topology of the products and rationalizes the observed stereochemistry. The β-onio-activated Michael systems thus generated represent a virtually unexplored class of compounds. The onio substituent in such compounds can be selectively replaced by a number of nucleophiles. Thus a series of Michael systems with donor functions in the β-position is easily synthesized. These compounds represent a source for useful further transformations, for example, cyclizations to quinolones, thiochromones, and pyrazoles.
